#!/usr/bin/env bash
. "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/common"

# CLI handling.
cpus=1
debug_vm=
debug=false
kgdb=false
kvm=false
# nokaslr:
# - https://unix.stackexchange.com/questions/397939/turning-off-kaslr-to-debug-linux-kernel-using-qemu-and-gdb
# - https://stackoverflow.com/questions/44612822/unable-to-debug-kernel-with-qemu-gdb/49840927#49840927
#   Turned on by default since v4.12
extra_append='console_msg_format=syslog nokaslr norandmaps panic=-1 printk.devkmsg=on printk.time=y'
extra_append_after_dash=
extra_flags=
extra_flags_qemu=
gem5opts=
gem5_fsbiglittle=false
gem5_restore_last_checkpoint=
lkmc_eval=
initrd=false
initramfs=false
memory=256M
nographic=true
prebuilt=false
rr=
root=
tmux=false
tmux_args=
trace_enabled=false
# A dummy value that is already turned on by default and does not produce large output,
# just to prevent QEMU from emitting a warning that '' is not valid.
trace_type=pr_manager_run
vnc=

parsed=$(getopt \
  -o "c:DdE:e:F:f:G:hIiKkl:m:PRrT:U:uVx${common_getopt_flags}" \
  -l "\
append,\
cpus:,\
debug,\
debug-vm,\
eval:,\
help:,\
gem5-biglittle,\
${common_getopt_flags_long}\
" \
-- "$@")
eval set -- "$parsed"
while true; do
  case "$1" in
    -c|--cpus)
      cpus="$2"
      shift 2
      ;;
    -D|--debug-vm)
      debug_vm="gdb -q -ex start --args \\
"
      shift
      ;;
    -d|--debug)
      debug=true
      extra_flags_qemu="${extra_flags_qemu} -S \\
"
      shift
      ;;
    -E|--eval)
      lkmc_eval="$2"
      shift 2
      ;;
    -e|--append)
      extra_append="${extra_append} ${2}"
      shift 2
      ;;
    -F)
      extra_append_after_dash="${extra_append_after_dash} lkmc_eval_base64=\"$(printf "${2}" | base64)\""
      shift 2
      ;;
    -f)
      extra_append_after_dash="${extra_append_after_dash} ${2}"
      shift 2
      ;;
    -G)
      gem5opts="$2 \\
"
      shift 2
      ;;
    --gem5-biglittle)
      gem5_fsbiglittle=true
      ;;
    -h|--help)
      echo "https://github.com/cirosantilli/linux-kernel-module-cheat#run" 2>&1
      exit
      ;;
    -I)
      initramfs=true
      shift
      ;;
    -i)
      initrd=true
      shift
      ;;
    -K)
      kvm=true
      shift
      ;;
    -k)
      extra_append="$extra_append kgdbwait"
      # For those who want to try KDB.
      #extra_append="$extra_append kgdbwait kgdboc=kbd"
      kgdb=true
      shift
      ;;
    -l)
      gem5_restore_last_checkpoint="${2}"
      shift 2
      ;;
    -m)
      memory="$2"
      shift 2
      ;;
    -P)
      prebuilt=true
      shift
      ;;
    -R)
      rr=replay
      shift
      ;;
    -r)
      rr=record
      shift
      ;;
    -T)
      trace_enabled=true
      trace_type="$2"
      shift 2
      ;;
    -U)
      tmux_args="$2"
      shift 2
      ;;
    -u)
      tmux=true
      shift
      ;;
    -x)
      nographic=false
      shift
      ;;
    -V)
      vnc="-vnc :0 \\
"
      shift
      ;;
    --)
      shift
      break
      ;;
    *)
      common_getopt_case "$@"
      ;;
  esac
done
common_setup
if "$debug" && "$kvm"; then
  echo 'error: -d and -K are incompatible' 1>&2
  exit 1
fi
if "$initrd" || "$initramfs"; then
  ramfs=true
else
  ramfs=false
fi
if [ -n "$lkmc_eval" ]; then
  if "$ramfs"; then
    initarg="rdinit"
  else
    initarg="init"
  fi
  extra_append="${extra_append} ${initarg}=/eval_base64.sh"
  extra_append_after_dash="${extra_append_after_dash} lkmc_eval=\"$(printf "$lkmc_eval" | base64)\""
fi
if "$nographic"; then
  if [ "$common_arch" = x86_64 ]; then
    extra_append="${extra_append} console=ttyS0"
  fi
  extra_flags_qemu="${extra_flags_qemu}-nographic \\
"
fi
if [ -n "$extra_append_after_dash" ]; then
  extra_append="${extra_append} - ${extra_append_after_dash}"
fi

if "$common_gem5"; then
  memory="${memory}B"
  if "$trace_enabled"; then
    gem5opts="${gem5opts} --debug-flags='${trace_type}' \\
"
  fi
  gem5_common="\
M5_PATH='${common_gem5_system_dir}' \\
${debug_vm}\
'${common_exec}' \\
--debug-file=trace.txt \\
${gem5opts}\
-d '${common_m5out_dir}' \\
"
  if "$gem5_fsbiglittle"; then
    if [ -n "$gem5_restore_last_checkpoint" ]; then
      extra_flags="${extra_flags}\
--restore-from='${common_m5out_dir}/$(ls -crt "$common_m5out_dir" | grep -E "$common_gem5_cpt_pref" | tail -n "$gem5_restore_last_checkpoint" | head -n 1)' \\
"
    fi
    cmd="${gem5_common}\
"${common_gem5_default_src_dir}/configs/example/arm/fs_bigLITTLE.py" \\
--big-cpus=2 \\
--cpu-type=atomic \\
--disk="${common_images_dir}/rootfs.ext2" \\
--dtb "${common_gem5_system_dir}/arm/dt/armv8_gem5_v1_big_little_2_2.dtb" \\
--kernel="${common_vmlinux}" \\
--little-cpus=2 \\
"
  else
    if [ -n "$gem5_restore_last_checkpoint" ]; then
      latest_cpt_basename="$(ls -crt "$common_m5out_dir" | grep -E "$common_gem5_cpt_pref" | tail -n "$gem5_restore_last_checkpoint" | head -n 1)"
      n="$(ls -1 "$common_m5out_dir" | grep -E "$common_gem5_cpt_pref" | sort -k 2 -n -t . | grep -n "$latest_cpt_basename" | cut -d : -f 1)"
      extra_flags="${extra_flags}-r ${n} \\
"
    fi
    gem5_common="\
${gem5_common}\
'${common_gem5_src_dir}/configs/example/fs.py' \\
--disk-image='${common_images_dir}/rootfs.ext2' \\
--kernel='${common_vmlinux}' \\
--mem-size='${memory}' \\
--num-cpus='${cpus}' \\
--script='${common_gem5_readfile_file}' \\
"
    if [ "$common_arch" = x86_64 ]; then
      if "$kvm"; then
        extra_flags="${extra_flags} --cpu-type=X86KvmCPU"
      fi
      cmd="\
${gem5_common}\
--command-line='earlyprintk=ttyS0 console=ttyS0 lpj=7999923 root=/dev/sda ${extra_append}' \\
"
    elif [ "$common_arch" = arm ] || [ "$common_arch" = aarch64 ]; then
      # TODO why is it mandatory to pass mem= here? Not true for QEMU.
      # Anything smaller than physical blows up as expected, but why can't it auto-detect the right value?
      cmd="${gem5_common}\
--command-line='earlyprintk=pl011,0x1c090000 console=ttyAMA0 lpj=19988480 rw loglevel=8 mem=${memory} root=/dev/sda ${extra_append}' \\
--dtb-file='${common_gem5_system_dir}/arm/dt/$([ "$common_arch" = arm ] && echo "armv7_gem5_v1_${cpus}cpu" || echo "armv8_gem5_v1_${cpus}cpu").dtb' \\
--machine-type=VExpress_GEM5_V1 \\
"
    fi
  fi
else
  mkdir -p "$common_qemu_run_dir"
  if [ -z "$debug_vm" ]; then
    serial_monitor="-serial mon:stdio \\
"
  else
    serial_monitor=
  fi
  if "$kvm"; then
    extra_flags="${extra_flags}-enable-kvm \\
"
  fi
  if "$kgdb"; then
    extra_flags_qemu="${extra_flags_qemu}-serial 'tcp::${common_gdb_port},server,nowait' \\
"
  fi
  if "$prebuilt"; then
    common_mkdir
    qemu_exec="qemu-system-${common_arch}"
  else
    qemu_exec="${common_qemu_exec}"
  fi
  extra_flags="${extra_flags_qemu}${extra_flags}"
  qemu_common="\
${debug_vm}\
${qemu_exec} \\
-device rtl8139,netdev=net0 \\
-gdb 'tcp::${common_gdb_port}' \\
-kernel '${common_linux_image}' \\
-m '${memory}' \\
-monitor 'telnet::${common_qemu_monitor_port},server,nowait' \\
-netdev 'user,hostfwd=tcp::${common_qemu_hostfwd_generic_port}-:${common_qemu_hostfwd_generic_port},hostfwd=tcp::${common_qemu_hostfwd_ssh_port}-:22,id=net0' \\
-no-reboot \\
${serial_monitor}\
-smp '${cpus}' \\
-trace 'enable=${trace_type},file=${common_qemu_run_dir}/trace.bin' \\
-virtfs 'local,path=${common_9p_dir},mount_tag=host_scratch,security_model=mapped,id=host_scratch' \\
-virtfs 'local,path=${common_buildroot_out_dir}/build,mount_tag=host_out,security_model=mapped,id=host_out' \\
${vnc}"
  if "$initrd"; then
    extra_flags="${extra_flags} -initrd '${common_images_dir}/rootfs.cpio' \\
"
  fi

  # Disk related options.
  if "$ramfs"; then
    # TODO why is this needed, and why any string works.
    root='root=/dev/anything'
  else
    if [ ! "$common_arch" = mips64 ]; then
      if [ -n "$rr" ]; then
        driveif=none
        rrid=',id=img-direct'
        root='root=/dev/sda'
        snapshot=
      else
        driveif=virtio
        root='root=/dev/vda'
        rrid=
        snapshot=,snapshot
      fi
      extra_flags="${extra_flags}-drive 'file=${common_qcow2_file},format=qcow2,if=${driveif}${snapshot}${rrid}' \\
"
      if [ -n "$rr" ]; then
        extra_flags="${extra_flags}\
-drive driver=blkreplay,if=none,image=img-direct,id=img-blkreplay \\
-device ide-hd,drive=img-blkreplay \\
"
      fi
    fi
  fi

  if [ -n "$rr" ]; then
    extra_flags="${extra_flags}\
-object filter-replay,id=replay,netdev=net0 \\
-icount 'shift=7,rr=${rr},rrfile=${common_qemu_rrfile}' \\
"
    virtio_gpu_pci=
  else
    virtio_gpu_pci="-device virtio-gpu-pci \\
"
  fi
  case "$common_arch" in
    x86_64)
      if "$kgdb"; then
        extra_append="${extra_append} kgdboc=ttyS0,115200"
      fi
      cmd="\
${qemu_common}\
-M pc \\
-append '${root} nopat ${extra_append}' \\
-device edu \\
"
    ;;
    arm|aarch64)
      if "$kgdb"; then
        extra_append="${extra_append} kgdboc=ttyAMA0,115200"
      fi
      if [  "$common_arch" = arm ]; then
        cpu=cortex-a15
      else
        cpu=cortex-a57
      fi
      # highmem=off needed since v3.0.0 due to:
      # http://lists.nongnu.org/archive/html/qemu-discuss/2018-08/msg00034.html
      cmd="\
${qemu_common}\
-M virt,highmem=off \\
-append '${root} ${extra_append}' \\
-cpu "$cpu" \\
${virtio_gpu_pci}\
"
    ;;
    mips64)
      if ! "$ramfs"; then
        root='root=/dev/hda'
        extra_flags="${extra_flags}-drive 'file=${common_qcow2_file},format=qcow2${snapshot}' \\
"
      fi
      cmd="\
${qemu_common}\
-M malta \\
-append '${root} ${extra_append}' \\
-cpu I6400 \\
"
    ;;
  esac
fi
if "$tmux"; then
  if "$common_gem5"; then
    eval "./tmu 'sleep 2;./gem5-shell -n ${common_run_id} ${tmux_args};'"
  elif "$debug"; then
    eval "./tmu ./rungdb -a '${common_arch} -L ${common_linux_variant}' -n ${common_run_id} ${tmux_args}"
  fi
fi
if [ -n "${1:-}" ]; then
  extra_flags="${extra_flags}${@} \\
"
fi
cmd="time \\
${cmd}${extra_flags}"
if [ -z "$debug_vm" ]; then
  cmd="${cmd}\
|& tee >(ts -s %.s > ${common_termout_file})\
"
fi
"${common_root_dir}/eeval" "$cmd" "${common_run_dir}/run.sh"
cmd_out=$?
if [ "$cmd_out" -ne 0 ]; then
  exit "$cmd_out"
fi

# Check if guest panicked.
if "$common_gem5"; then
  # We have to do some parsing here because gem5 exits with status 0 even when panic happens.
  #
  # Grepping for '^panic: ' does not work because some errors don't show that message
  panic_msg='--- BEGIN LIBC BACKTRACE ---$'
else
  panic_msg='Kernel panic - not syncing'
fi
if grep -E -e "$panic_msg" -q "$common_termout_file"; then
  echo 'Simulation error detected by parsing logs. Exiting with status 1.'
  exit 1
fi
